1. Field
The present disclosure relates to a method for signaling a facsimile pass through mode over a VOIP voice service.
2. Introduction
Due to the advancement in high speed bandwidth transmission to home users, many cable operators and Passive Optical Network operators have chosen to provide Triple Play services (Voice, Video and Data services) over an IP backbone. For example, Verizon provides Triple Play services to its Gigabit Passive Optical Network (GPON) customers and uses Voice Over Internet Protocol (VOIP or Voice Over IP), Session Initiation Protocol (SIP) and Real Time Protocol (RTP) for voice services. Based on an end user needs, various types of Optical Network Terminals (ONT) are chosen.
SIP is used as a signaling protocol between Optical Network Terminals (ONTs) via the Optical Line Terminals (OLTs) and the endpoints are connected to the ports available in the Optical Network Terminals. Verizon supports Class-5 supplementary services for voice.
When using a facsimile pass through mode of signaling over VOIP voice service in ONTs, there is a need for using SIP signaling to indicate a facsimile pass through, rather than indicate a two way call.
The following steps show how the FAX Pass thru mode is typically chosen: First, User A goes off hook and dials User B's number. This information gets passed to User B via SIP signaling from one ONT device to another via Optical Line Terminals (OLT).
Next, User B is alerted and goes off hook and answers the call. Both Users A and B use a vocoder, such as G711U codec, via SDP negotiation done via INVITE-200 OK-ACK messages.
Next, according to “draft-ietf-sipping-realtimefax-01.txt” and “draft-mule-sip-t38callflows-01.txt”, User B would send a re-INVITE request back to User A requesting codec T.38 only if it supports it. But, in the case where User B does not support the T.38 codec, it would stay with the already negotiated codec G711U codec.
And next, when User A sends a fax detect tone, User B detects it and starts the fax reception. But, user A is not notified that the fax tone is detected and therefore, the call status of User A as seen on Network switching device OLT (Optical Line Termination) is “2 way” instead of a “fax call”. This is a problem with facsimile communications in connection with OLTs and ONTs.
Therefore, when it comes to billing the caller for a “fax call” made, the status of this call would be shown as a “2way” call instead of a “fax call”. Applicant is not aware of a solution provided in relevant standards for a method for signaling a facsimile pass through mode over a VOIP voice service.
There is yet a further need to provide enhanced tracking of calls, for enhancing usage information, quality of service and improved billing, which can use many components already found in communication systems utilizing VOIP voice service. Thus, a method that addresses these issues and problems would be considered an improvement in the art.